Plastic doors and door frames for trailers



4 Sheets-Sheet 1 IN VEN TOR.

AT TOR/V573.

S. LEVlTT PLASTIC DOORS AND DOOR FRAMES FOR TRAILERS Canaan/WW Jan. 27 1959 Filed Nov. so, 1955 4 Sheet s-Sheet 2 s. LEVITT PLASTIC DOORS AND DOOR FRAMES FOR TRAILERS ,ullllllum Jan. 27, 1959 Filed Nov. 30, 1955 -r' m mmn||......

INVENTOR.

SEMOND LEVITT ATTORNEYS.

Jan. 27, 1959 s. LEVlTT 2,

PLASTIC DOORS AND DOOR FRAMES FOR TRAILERS Filed Nov. 30, 1953 4 Sheets-Sheet a INVENTOR.

SEMOND LEVITT 38' 60 e2 '32 '30 e2 60 38 BY v.

A 7' TOR/VEYS.

Jan. 27, 1959 s, L v

PLASTIC DOORS AND DOOR FRAMES FOR TRAILERS Filed Nov. 30, 1953 4 Sheets-Sheet 4 I 1 r I AT TOR/VEYS.

United States Patent PLASTIC DOORS AND DOOR FRAMES FoR TRAILERS V I Semond Levitt, Philadelphia, Pa., assignor, by mesne assignments, to Fruehauf Trailer Company, Detroit, Mich., a corporation of Michigan Application November 30, 1953, Serial No. 394,948

8 Claims. (Cl. 296-106) This invention relates to trailers, conventional or refrigerated, equipped with preformed reinforced plastic alone or in combination with Wood. As is well known,

wood absorbs liquids and odors, has low impact resistance and is impossible to clean with hot water or live steam. When the doors become laden with moisture they swell and exert excessive strain on the hinges. Upon drying, the wooden doors shrink and warp and very seldom fit properly.

I Metallic doors, while they do not absorb moisture, are nevertheless good heat conductors, weighty and subject to corrosion due to electrolysis, rusting or contact with corrosive chemicals or materials. Such corrosion results in heat loss and structural failure. Additionally, aluminum turns certain commodities, such as meat,

black.

Door frames are generally built of heavy oak members which are subject to the same evils as doorsnamely, rotting, expansion, contraction, swelling, odor absorption, and so forth.

It is the primary object of the present invention to provide doors and/or door frames for trailers, particularly refrigerated trailers, which are made of preformed reinforced plastics which overcome the disadvantages of the conventional trailer doors and frames as noted hereabove.

Another object of the invention is to provide reinforced plastic doors and door frames which, while considerably lighter than wooden or metal doors and door frames, are, because of their special construction, structurally strong, durable and impact resistant.

Another object of the invention is to provide reinforced plastic doors and door frames which are corrosion resistant, heat insulating, warp proof, will not absorb or transfer odors, and capable of being thoroughly cleaned by hot water or live steam.

Another object of the invention is to provide reinforced plastic doors molded to include vertical ribs at their inner walls to serve the dual purpose of imparting impact strength thereto and of allowing proper circulation of refrigerated air about cargo adjacent the doors.

Another object of the invention is to provide reinforced plastic doors molded to include vertical and horizontal ribs at the inner and outer surfaces of their inner walls which impart an impact strength to the doors many times in excess of plywood and light gage metals, this notwithstanding the fact that the reinforced plastic doors are considerably lighter than wooden or metallic doors.

Another object of the invention is to provide reinforced plastic doors and door frames including a nesting step construction to effect a tight closure of the doors against themselves and against the frames.

Another object of the invention is to provide reinforced plastic doors for trailers of such shape and construction "ice that each door half may be fabricated from the same mold.

Yet another object of the invention is to provide a trailer in which maintenance and production costs are reduced because the doors and door frames are easily and economically molded into desired sizes and shapes of preformed reinforced plastics, which molded preforms are assembled in the trailer with a minimum of manipulation.

These and other objects of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

Figure 1 is a rear elevational view of a trailer incorporating the invention;

Figure 2 is an enlarged, broken away, sectional view taken on the line 22 of Figure 1;

Figure 3 is an enlarged sectional view taken on the line 33 of Figure 1;

Figure 4 is a top elevational view of a door frame;

Figure 5 is an elevational view of the inner face of the rear wall of the door;

Figure 6 is a view similar to Figure 5 showing the outer face of the rear wall of the door;

Figure 7 is a sectional view taken on the line 7-7 of Figure 5;

Figure 8 is a sectional view taken on the line 8-8 of Figure 6; 1

Figure 9 is an enlarged sectional view taken on the line 9--9 of Figure 5; v v

Figure 10 is an' enlarged sectional view taken on the line 1010 of Figure 6;

Figure 11 is an enlarged sectional view taken on the line 11-11 of Figure 5; v v y Figure 12 is an enlarged sectional view takenon the line 12--12 of Figure 5;

Figure 13 is a fragmentary rear elevational view of a trailer showing a modification of the invention;

Figure 14 is an enlarged, broken away, sectional view taken on the line 14-14 of Figure 13;

Figure 15 is an elevational view of the door of the invention shown in Figure 13;

Figure 16 is a sectional view taken on the line 16-16 of Figure 15;

, Figure 17 is a vertical sectional view through a modi fied form of the door shown in Figure 13; and

Figure 18 is a fragmentary enlarged horizontal sectional view of a modification of the doors shown in Fig ures 1-12.

Special reference will now be made to the drawings in which similar reference characters are used for corresponding elements throughout.

In its broadest aspect the present invention comprises a trailer, conventional or refrigerated, in which the doors alone or in combination with the door frames are con structed of preformed reinforced plastics. The reinforcement molded into theplastics may be any fibrous material, such as fibrous glass, nylon, rayon, asbestos,

cotton, sisal, etc. Fibrous glass is preferred because it is the least hygroscopic, most uniform and strongest fiberknown.

While any plastic having the desired characteristics of strength. moldability, corrosion resistance and moisture resistance may be used, low pressure plastics are and/or catalyst to solid infusible masses. Examples of such polyester resins are the Paraplex P Series Resins made by Rohm & Haas Company, Philadelphia, Pa., and Vibrinf resins made by Naugatuck ,Chemical, Division 'ofUnited States Rubber Company, Naugatuck; Connecticut. v

With the polyester resins fibrous glass matsare generally used -as reinforcement. These mats are preferably fibrous 'glass'e'ontainin'g low solubility or high solubility powdered polyester resin binders such as "are made and sold asfFiberglas.PlasticsReinforcing Mat '(L. S. or H. S. binder) by Owens-Corning Fiberglas Corporation, Toledo, Ohio. The fibrous glass mats and polyester resins are molded into the desired shapes and sizes, with or without pigments, by -conventional techniques.

Since the preformed reinforced plastic doors and door frames have their greatest utility for refrigerated trailers, the invention has been illustrated in association with refri'gerate'd trailers.

Such a trailer is generally shown at and includes among other things insulated sides 12 to the rear vertical edges of which are secured wooden planks 14. Door jambs are provided, each consisting of a vertical, preferably metallic hollow corner piece 16 embracing an inner wooden post 18, said jam b'being spaced from the wooden plank-14.

A pair of vertically extending door frames 20 are molded of the reinforced plastic, each including front and rear vertically extending flanges 22 and 24, a portion of the intermediate Wall including a step 26 for apurpose soon to appear. Fibrous glass insulating mats 28 are placed be'tWeen't-he wall of the door-frame and the outer skin 30 of the trailer side, and appropriate securing'means 32 and 34 are used to attach the 'fianges '22 and 24 of the door frame to the wooden plank and the door jamb 'respectiveIy, on both rear vertical ends of the trailer.

Each door comprises a shell portion 36 and a facing sheet 38. The facing sheet may be metallic or a :reinforced plastic molded with the shell. The shell, molded bf thereinfor'ced plastic, includes an inner wall 40 and a peripheral w'all 42' having a peripheral flange 44. That ortion of the peripheral wall 42 which is adjacent the door frame is of step construction 46 to nest into and cooperate with the step formation 26'of the door frame, as shown clearly in Figure 2. Appropriate rubber gaskets or grommets 48 may be interposed between the cooperating steps of the door and door frarne and between the door'and door jamb to effect "a tight closure. Appropriate hinge plates StL-Figure 3, may be bolted as at SZ'and 54 to the door-shell and facing plate to effect a hinge connection as at 56'between the doorandthe door jarnb.

That portion 58 of the peripheral wall 42 opposite the step formation 46, the same constituting the meetin'g edges of the-doors, includes an integrally molded hollow rib 60 embracing an inner, preferably wooden, post 62. This integral post-carrying rib is designed so that the door shellca'n readily come out of the mold in the manufacture thereof and "also serves to impart strength and rigidity to the "doors at a critical area, namely their meeting edges.

To further impart strength and rigidity to the plastic shell, the inner wall 40 thereof is provided with various post-carrying integrally molded ribs. The outer face *64 of 'the wall 36 is provided with-transversely spaced, vertically extending hollow ribs 66 which embrace vertically extending, preferably wooden, posts 68 whereas theinner face 70 of the wall 40 is provided with vertically spaced, horizontally extending, preferably triangularhollow ribs .72 :embracing preferably wooden slats .74. Thus the inner wan 40of the shell is rendered rigid and impact resistance in an directions. The'ribs 66 serve'the 'additionalfunction of allowing circulation of refrigerated air about cargo adjacent the doors.

When, as preferred, the facing plate 38 'is metallic, fibrous glass insulating. mats 7 6 arepositioned in the shell I16and'aftentheperipheral.flange 441hasbeentreated with chromates, the facing plate is secured to the flange 44 by means of rivets 78 and is further secured to the opposite post-carrying rib 60 by means of bolts and nuts 80. Any suitable latching means 82 may be associated with the doors.

In the modifications shown in Figures 13-17, the abovedescribed doors and frames are assembled on the rear of the refrigerated trailer. Each door is provided with a smaller, auxiliary peep door construction 84.

This construction includes a smaller rectangular preformed reinforced plastic door frame 86 which is appropriately secured, as at 88, to an auxiliary frame 90 provided in an opening 92 in the larger door. The said door frame has a peripheral step formation 94 and also may carry a secreen 96 at its innerend.

The auxiliary smaller door 98 is fabricated of a preformed reinforced plastic shell 100 having a rear wall 102 and a peripheral wall 104 of step formation 106 which cooperates with the step formation '94 of the frame to nest therein, there being appropriate rubber gaskets or grommets 1'08 interposed between the steps to effect a tight closure. The facing plate 110 of the door may be metallicand appropriately secured to the outer periphery of the shell after the latter has been filled with an insulating material 112. The facing plate may also be fabricated of the reinforced plastic, as at 114, in which it is secured to the periphery of the shell by appropriate sealing compounds, or it may be molded as an integral unit with the shell.

Appropriate hinges 116 and latches 118 may be associated with the auxiliary or peep doors.

"To "improve the closure of the doors they may be'modified to "include the step formation at their .meeting edges aspshown in Figure 1'8. This is accomplished 'by providing a vertical wooden .post 120 which is of such horizontal cross-section as to include a portion 122 which fits into the step portion 58 of 'the peripheral wall of one of the door shell and a step portion 124 overlapping the meeting edges of thedoors. The post 120 iszsecured to .one of the doors by means of arecesse'd screw or bolt 126 extending through 'thefa'ce plate 38, the rib 60, the post 62and the post 120. The step 124 carries airubber gasket or grommets 1'28 and is such as to nest tightly with the step 58 of the peripheral wall of the shell of the adjacent door. Thus both doors are identical and can be made of the same mold and the post 120 can be readily secured to either door, in the manner described, to give the desired tight closure. An oifsetstriker plate .130 may be secured as .at 132 to one of the doors.

While preferred embodiments .of the invention have been shown .and described hereabove, minor variations may be made byskilled artisans without departing :from the invention and thescope of .the appended claims.

.I claim:

.1. In a trailer having a-roof, sides and .door jarnbs at their .rear vertical ends, plastic door frames secured .to the sides and jarnbs and plastic doors hinged to the'jarnbs and cooperating with the frames, said doors including inner vertical edges ofstep cross-section, one portion of said edges -of onedoor cooperating with an adjac-entportion of said edges of the other door tto form meeting edges and a vertical'post securedin the step'of one door, said :post having a step cross-section to provide a portion adapted to overlap the tmeeting v edges ,andnest in .the step of 'theiother door to eifec't a tight closure.

:2. In a motor vehicle having atroof, sides andtdoor jambs at their .rear vertical ends, door frames secured to the sides and jambs andplastic doorshinged to the jamhs and cooperating withthe frames, said doors including'inner'vertical edges of step cross-section, one portion of said edges of one door cooperating with an'adjacent portion'of said edges of the other door'toform meeting edges and a vertical post secured in the step of one door, "Said post having a step cross=section to provide a portion adapted to overlap the meeting edges and nest in the step of the other door to effect a tight closure.

3. The combination of claim 2 wherein each door includes an inner shell and an outer face plate secured to said shell, the inner face of said shell including integral horizontal and vertical ribs to impart strength and rigidity thereto.

4. The combination of claim 2 wherein each inner edge portion forming the meeting edges of the door is provided along its length with an integral hollow rib and post retained therein, and means securing said post of step cross-section to one of said ribs and said post retained therein. 1

5. In a refrigerated trailer of the type including a roof and insulated sides having door jambs at the rear vertical ends thereof, insulated reinforced preformed plastic door frames secured to the sides and jambs, said frames including reinforced plastic shells having insulating material therein; insulated reinforced preformed plastic doors hinged to the jambs and cooperating with the door frames, each door including a shell having an inner wall and an outer peripheral edge, a face plate secured to said outer edge, and insulating material in the shell between the face plate and the inner wall, the inner wall of each door shell having integral horizontal ribs on one face and integral vertical ribs on the opposite face thereof to impart strength and rigidity thereto, the inner wall of each frame being of'step formation and the corresponding wall of the shell of each door being also of step formation to cooperate with the frame steps; and gaskets interposed between the meeting portions of said steps.

6. In a refrigerated trailer of the type including a roof and insulated sides having door jambs at the rear vertical ends thereof, insulated reinforced preformed plastic door frames secured to the sides and jambs, said frames including reinforced plastic shells having insulating material therein; insulated reinforced preformed plastic doors hinged to the jambs and cooperating with said door frames, each of the vertical meeting edges of said doors being provided the length thereof with an integral hollow rib and a post retained therein, each door including a shell having an inner wall and an outer peripheral edge, a face plate secured to said outer edge, and insulating material in the shell between the face plate and the inner wall, the inner wall of each door shell having integral horizontal ribs on one face and integral vertical ribs on the opposite face thereof to impart strength and rigidity thereto, the inner wall of each frame being of step' formation and the corresponding wall of the shell of each door being also of step formation to cooperate with the frame steps.

7. In a refrigerated trailer having a roof and insulated sides and door jambs at their rear vertical ends, insulated reinforced preformed plastic door frames secured to the sides and jambs, said frames including reinforced plastic shells having insulating material therein; and insulated reinforced preformed plastic doors hinged to the jambs and cooperating with the door frames, each door including a shell having an inner wall and an outer peripheral edge, a face plate secured to said outer edge, and insulating material in the shell between the face plate and the inner Wall, the inner wall of each door shell including integral horizontal ribs on one face and integral vertical ribs on the opposite face thereof to impart strength and rigidity thereto, the inner wall of each frame being of step formation and the corresponding wall of the shell of each door being also of step formation to cooperate with the frame steps.

8. In a refrigerated trailer having 'a roof and insulated sides and door jambs at their rear vertical ends, insulated reinforced preformed plastic door frames secured to the sides and jambs, said frames including reinforced plastic shells having insulating material therein; and insulated reinforced prefonned plastic doors hinged to the jambs and cooperating with the door frames, each door including a shell having an inner wall and an outer peripheral edge, a face plate secured to said outer edge, and insulating material in the shell between the face plate and the inner wall, the inner wall of each door shell including integral horizontal ribs on one face and integral vertical ribs on the opposite face thereof to impart strength and rigidity thereto.

References Cited in the file of this patent UNITED STATES PATENTS 1,930,635 Wessling Oct. 17, 1933 1,989,158 Seeger et a1. Jan. 29, 1935 2,071,236 Pierce Feb. 16, 1937 2,223,778 Black Dec. 3, 1940 2,459,765 Black Jan. 18, 1949 2,571,600 Nave Oct. 16, 1951 2,581,867 Krohnert Jan. 8, 1952 2,613,509 Philipp Oct. 14, 1952 2,640,230 Eck et a1. June 2, 1953 2,731,682 Evans Jan. 24, 1956 FOREIGN PATENTS 686,163 Great Britain Feb. 4, 1949 OTHER REFERENCES Plastics Body Construction, article in Automobile Engineer of June 1952, vol. 42, No. 554, pp. 223-229.

Glass Fiber Insulation, article in Scientific American of November 1944, page 218. 

